#btns {
    margin: auto;
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translateX(-50%) translateY(-50%);
    text-align: center;
}

#roolName {
    font-size: 100px;
    margin: auto;
    position: absolute;
    left: 50%;
    top: 35%;
    transform: translateX(-50%) translateY(-50%);
    text-align: center;
}

html {
    font-size: 100%;
}

@media screen and (max-width:680px) {
    #roolName {
        font-size: 40px;
    }
    #btns {
        width: 100px;
    }
    #btns button {
        margin-top: 10px;
    }
}

@media screen and (max-height:400px) {
    #roolName {
        font-size: 35px;
    }
}